Drug Information

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Summary of Interactions with Vitamins, Herbs, & Foods

Replenish Depleted Nutrients

Oral corticosteroids reduce absorption of calcium1 and interfere with the activation and metabolism of the vitamin,2, 3, 4, 5 increasing the risk of bone loss. Doctors can measure levels of activated vitamin D (called 1,25 dihydroxycholecalciferol) to determine whether a deficiency exists; if so, activated vitamin D is only available by prescription. A study of rheumatoid arthritis patients treated with low amounts of prednisone found that those who received 1,000 mg of calcium per day plus 500 IU of vitamin D per day for two years experienced no bone loss during that time period.6 An analysis of properly conducted trials concluded that supplementation with vitamin D and calcium was more effective than placebo or calcium alone in protecting against corticosteroid-induced osteoporosis.7 Most doctors recommend 1,000 mg of calcium and 400–800 IU vitamin D per day for the prevention of osteoporosis.

Oral corticosteroids reduce absorption of calcium and interfere with the activation and metabolism of the vitamin,22, 23, 24, 25, 26 increasing the risk of bone loss. Doctors can measure levels of activated vitamin D (called 1,25 dihydroxycholecalciferol) to determine whether a deficiency exists; if so, activated vitamin D is only available by prescription. A study of rheumatoid arthritis patients treated with low amounts of prednisone found that those who received 1,000 mg of calcium per day plus 500 IU of vitamin D per day for two years experienced no bone loss during that time period.27 An analysis of properly conducted trials concluded that supplementation with vitamin D and calcium was more effective than placebo or calcium alone in protecting against corticosteroid-induced osteoporosis.28 Most doctors recommend 1,000 mg of calcium and 400–800 IU vitamin D per day for the prevention of osteoporosis.

Preliminary data suggest that corticosteroid treatment increases chromium loss and that supplementation with chromium (600 mcg per day in the form of chromium picolinate) can prevent corticosteroid-induced diabetes.43 Double-blind trials are needed to confirm these observations.

A controlled trial found that a single dose of the synthetic corticosteroid dexamethasone suppressed production of melatonin in nine of 11 healthy volunteers.46 Further research is needed to determine if long-term use of corticosteroids interferes in a meaningful way with melatonin production, and whether supplemental melatonin would be advisable for people taking corticosteroids.

Oral corticosteroids increase the urinary loss of potassium.49 This may not cause a significant problem for most people. Individuals who wish to increase potassium intake should eat more fruits, vegetables, and juices rather than taking over-the-counter potassium supplements, which do not contain significant amounts of potassium.

Corticosteroids may increase the loss of vitamin B6.58 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.59 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

Reduce Side Effects

In some people, treatment with corticosteroids can impair wound healing. In one study, topical or internal vitamin A improved wound healing in eight of ten patients on corticosteroid therapy.64 In theory, vitamin A might also reverse some of the beneficial effects of corticosteroids, but this idea has not been investigated and no reports exist of such an interaction in people taking both vitamin A and corticosteroids. People using oral corticosteroids should consult with a doctor to determine whether improved wound healing might outweigh the theoretical risk associated with concomitant vitamin A use.

Although blood levels of vitamin A appear to increase during dexamethasone therapy65—most likely due to mobilization of the vitamin from its stores in the liver evidence from animal studies has also indicated that corticosteroids can deplete vitamin A from tissues.66

Preliminary data suggest that corticosteroid treatment increases chromium loss and that supplementation with chromium (600 mcg per day in the form of chromium picolinate) can prevent corticosteroid-induced diabetes.73 Double-blind trials are needed to confirm these observations.

Support Medicine

One preliminary study found that in people with fibrosing alveolitis (a rare lung disease), supplementation with 600 mg N-acetyl cysteine three times per day increased the effectiveness of prednisone therapy.79

Explanation Required

Licorice (Glycyrrhiza glabra) extract was shown to decrease the elimination of prednisone in test tube studies.85 If this action happens in people, it might prolong prednisone activity and possibly increase prednisone-related side effects. A small, controlled study found that intravenous (iv) glycyrrhizin (an active constituent in liquorice) given with iv prednisolone prolonged prednisolone action in healthy men.86 Whether this effect would occur with oral corticosteroids and liquorice supplements is unknown.

An animal study has shown that glycyrrhizin prevents the immune-suppressing actions of cortisone—the natural corticosteroid hormone produced by the body.87 More research is necessary to determine if this action is significant in humans taking oral corticosteroids. Until more is known, people should not take liquorice with corticosteroids without first consulting a doctor.

Use of buckthorn (Rhamnus catartica, Rhamnus frangula, Frangula alnus) or alder buckthorn (Rhamnus catartica, Rhamnus frangula), for more than ten days consecutively may cause a loss of electrolytes (especially the mineral potassium). Because corticosteroids also cause potassium loss, buckthorn or alder buckthorn should be used with caution if corticosteroids are being taken.94

Use of buckthorn (Rhamnus catartica, Rhamnus frangula, Frangula alnus) or alder buckthorn (Rhamnus catartica, Rhamnus frangula), for more than ten days consecutively may cause a loss of electrolytes (especially the mineral potassium). Because corticosteroids also cause potassium loss, buckthorn or alder buckthorn should be used with caution if corticosteroids are being taken.97

Taking the oral corticosteroid methylprednisolone with grapefruit juice has been shown to delay the absorption and increase the blood concentration of the drug.100 The mechanism by which grapefruit juice increases the concentration of methylpredniolone in the blood is not known, but it is suspected that it may interfere with enzymes in the liver responsible for clearing the drug from the body. In certain people, grapefruit juice may, therefore, enhance the effects of methylprednisolone. The combination should be avoided unless approved by the prescribing doctor.

Corticosteroids may increase the body’s loss of magnesium.103 Some doctors recommend that people taking corticosteroids for more than two weeks supplement with 300 to 400 mg of magnesium per day. Magnesium has also been reported to interfere with the absorption of dexamethasone.104

Pomegranate juice has been shown to inhibit the same enzyme that is inhibited by grapefruit juice.109, 110 The degree of inhibition is about the same for each of these juices. Therefore, it would be reasonable to expect that pomegranate juice might interact with oral corticosteroids in the same way that grapefruit juice does.

In some people, treatment with corticosteroids can impair wound healing. In one study, topical or internal vitamin A improved wound healing in eight of ten patients on corticosteroid therapy.115 In theory, vitamin A might also reverse some of the beneficial effects of corticosteroids, but this idea has not been investigated and no reports exist of such an interaction in people taking both vitamin A and corticosteroids. People using oral corticosteroids should consult with a doctor to determine whether improved wound healing might outweigh the theoretical risk associated with concomitant vitamin A use.

Although blood levels of vitamin A appear to increase during dexamethasone therapy116—most likely due to mobilization of the vitamin from its stores in the liver evidence from animal studies has also indicated that corticosteroids can deplete vitamin A from tissues.117

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.

Please read the disclaimer about the limitations of the information provided here. Do NOT rely solely on the information in this article. The Aisle7 knowledgebase does not contain every possible interaction.

The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.

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